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US 6,243,487 B1Granted
Pattern exposure method using electron beam
AssigneeNEC Corporation
InventorKen Nakajima
Life of this patent
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Abstract
Disclosed is a pattern exposure method for conducting an overlay exposure to a base pattern previously formed by using electron beam, which has the steps of: 1) dividing a group of patterns formed on the base pattern into arbitrary regions; 2) calculating an area density of the base pattern in each of the arbitrary regions; 3) generating a pattern according to the area density; 4) conducting sub-exposure using the pattern; and 5) conducting main exposure to expose a desired pattern.
Claims8
A pattern exposure method for conducting an overlay exposure to a base pattern previously formed by using an electron beam, comprising the steps of:
- 1) dividing a group of patterns formed on said base pattern into arbitrary size regions;
- 2) calculating an area density of said base pattern in each of said arbitrary size regions;
- 3) generating a first pattern according to said area density of said base pattern in each of said arbitrary size regions;
- 4) conducting sub-exposure using said first pattern;
- and
- 5) conducting main exposure using a second pattern to expose a desired pattern,
- wherein exposure quantity is set by subtracting an exposure quantity of energy intensity accumulated by said sub-exposure from the optimum exposure quanity of the second pattern.
4 more elements
Dependencies are inferred from the claim text.